1. Field of the Invention
This invention relates to a damping material which is pasted on the head suspension of disk units and to a head suspension with the damping material.
2. Description of the Prior Art
The head for use in magnetic disk units such as a hard disk drive (HDD), a magneto optical drive and the like floats by keeping a minute space on a magnetic disk which is spinning at a high speed, thereby carrying out read/write of information on the disk. With the demand for high recording density in recent years, the head size and floating quantity have been minimized, so that, in order to effect read/write of information on the magnetic disk exactly, it is important to locate the head part precisely while suppressing its vibration.
As shown in FIGS. 10A to 10C, the structure of a head suspension is generally constructed with a magnetic head 1, a head supporting spring 2 which supports the head and a fixing block 3 which fixes the suspension.
Since the aforementioned head part receives vibration from, for example, a drive unit of the head 1 and a motor for use in the spin drive of disks, the head supporting spring 2 formed with a plate spring or the like is deformed and the position of the head 1 slips off, thus frequently causing errors in reading and writing. In consequence, in order to decrease or remove vibration in the head supporting spring 2, a method has been proposed in which a damping material 4 prepared by laminating a constraining body and a visco-elastic body is pasted on the linear part of the head supporting spring 2 (Japanese Patent Publication No. Hei. 4-8868). According to this method, the visco-elastic body interposed between the vibrating head supporting spring 2 and the constraining body deforms accompanied by the vibration deformation of the head supporting spring 2, thereby generating internal resistance (molecular friction) which converts the vibration energy into thermal energy, and thus exerting a damping effect in which the vibration energy the head suspension will directly receive is greatly reduced.
It is important that the constraining body has high rigidity in order to improve the just described damping effect, and a metal plate such as of stainless steel is generally used as the constraining body. Also, an adhesive, rubber or the like is used as the visco-elastic body.
However, since vibration absorption of the head suspension disclosed in Japanese Patent Publication No. Hei. 4-8868 is still insufficient, further improvement of the effect has been expected. Since the recent tendency toward multi-media performance demands high memory capacity, high memory density and high speed read/write, it becomes more and more important to precisely locate the head and head suspension parts while suppressing their vibration, in order to effect read/write of information on the magnetic disk exactly.